Copying apparatus

ABSTRACT

An apparatus for forming images on light-sensitive web material and transferring them to copying material comprises a rotatable slotted hollow drum having processing means disposed about its periphery and having the lightsensitive web material trained from a supply roll inside the drum over the outer surface of the drum to holding means in the slot of the drum, which means include means operable when the drum is in a rest position to displace the web material outwards and into engagement with fixed web propelling means so that, whenever desired, the drum may be stopped and a used length of the web material removed from its surface and replaced by a fresh length drawn from the supply roll. The material leading off the drum is severed by causing the propelling means or renewed drum rotation to tear it off, or by causing the same to draw it taut against a knife edge that cuts it off.

i United States Patent [19] van Meijel et' al.

[111 3,829,208 451 Aug. 13, 1974 COPYING APPARATUS [75] Inventors: Henricus J. M. van Meiiel, Venlo; Martin L. van der Sterren, Horst,

[21] Appl. No.: 222,916

[30] Foreign Application Priority Data Feb. 11, 1971 Netherlands 7101848 [52] US. Cl. 355/3, 355/13 [51] Int. Cl G03g 15/00 [58] Field of Search 355/3, 13.; 95/17.

[56] References Cited I UNITED STATES PATENTS 439,121 10/1890 Crane 95/17 3,453,046 7/1969 Engeland 355/13 Primary Examiner-John M. Horan Attorney, Agent, or FirmAlbert C. Johnston 7] ABSTRACT An apparatus for forming images on light-sensitive web material .and transferring them to copying material comprises a rotatable slotted hollow drum having processing means disposed about its periphery and having the lightsensitive web material trained from a supply roll inside the drum over the outer surface of the drum to holding means in the slot of the drum, which means include means operable when the drum is in a rest position to displace the web material outwards and into engagement with fixed web propelling means so that, whenever desired, the drum may be stopped and a used length of the web material removed from its surface and replaced by a fresh length drawn from the. supply roll. The material leading off the drum is severed'by causing the propelling means or renewed drum rotation to tear it off, or by causing the same to draw it taut against a knife edge that cuts it off.

9 Claims, 3 Drawing Figures 1 COPYING APPARATUS This invention relates to a copying apparatus which is especially useful for electrophotographic copying work, though not limited to such use.

A copying apparatus disclosed in Dutch Pat. Application No. 68,06739, FIGS. 2, 3 and 4, makes use of a rotatable hollow drum having a slot in its peripheral wall and housing a supply roll of a light-sensitive or sensitizable web so that a length of the web may be trained from the roll through the slot and over the outer surface of the drum in position to be carried upon each revolution of the drum through processing stations whereby an image is formed on said web length and then is transferred from it onto a copying materiaL'The apparatus also includes means for displacing said web length away from the drum surface so as to replace it by a further length of the web drawn from the roll after a number of revolutions of the drum, which means are operated in correlation with web holding means supported by the drum in the immediate vicinity of the slot in the drum. 7

According to that disclosure, the used web length is fed back through the slot and wound onto another roll inside the drum. For that purpose the web holding means in the immediate vicinity of the slot is released and the other roll is driven so that the used web length is drawn from the periphery of the drum through the slot and onto the other roll and a fresh length of the web is drawn simultaneously from the supply roll onto the drum surface.

That known construction is rather complicated, and it is particularly disadvantageous'in that only a small quantity of web material can be stored on the supply roll, because the maximum diameter of that roll is considerably less than half the inside diameter of the drum. Moreover, since the stock of web material is moved progressively from one to the other of two rolls disposed eccentrically inside the drum, it is not possible to keep the drum balanced and consequently, especially at a high drum speed, vibrations may occur so as to diminish the sharpness of the images obtained on the copying material.

The object of this invention is to provide an improved copying apparatus of a type similar to that'described above but by which the above mentioned disadvantages of the known apparatus may be overcome or substantially alleviated.

According to the present invention, use is made of a rotatable hollow drum having a slot in its peripheral wall and housing a supply roll of light-sensitive or sensitizable web material, witha length of. the web trained from the roll over the drum surface as above described, together with web displacing means which comprise web holding means supported by the drum in the immediate vicinity of the slot in the drum and web propelling means arranged at a fixed location outside the drum so that, when a used length of the web is to be replaced, the drum may be brought temporarily to rest in a position in which an end portion of the web engaged by said holding means may be passed to, and then drawn away from the drum by, said propelling means so as to ,draw a fresh length of the web into working position on the surface of the drum.

According to a further feature of the invention, the web holding meanson the drum and the web propelling means outside the drum are so arranged that when the fresh length of the web has been brought into working position, a movement of a lead of the web extending between those means will cause the used length of web drawn away from the drum to be severed from the trailing part of the web, thus leaving a new end portion of the web being engaged and held by the holding means as the 'drum rotates anew. This severing action advantageously is effected with the aid of a web cutting device against which that web lead is drawn just before, or in consequence of, the renewed rotation of the drum.

In apparatus embodying this invention the web supply roll can be simply supported onthe axis of the drum and can hold a very large store of the web material, up to a maximum roll diameter approaching the full inside diameter of the drum. Also, the web roll need not itself by provided with any drivingmeans.

It has been proposed previously in other relationships to transport a used length of web material outward from a rotatable drum, for example, as disclosed in FIGS. 5 and 6 of said Dutch jPat. Application No. 68,06739, or as disclosed in Dutch Pat. Application No. 65.17212. In said FIGS. 5 and 6, the web material is secured to the drum wall in a number of layers from which a used layer can be peeled off by rotating the drum in a direction opposite to that used during copying. Howevenonly a limited stock of web material can be provided in that way, due to the fact that as layers of the stock are peeled off the remaining outer layer must still be in effective mating contact with the processing units arranged around the drum. According to Dutch Pat. Application No. 65,17212 a large storage spool may be fitted centrally inside the drum, but in this case the web material is used only once and is cut off and removed before or after each exposing operation. Furthermore, only a small portion of the drum periphery can be used effectively for copying, so that the periphery of the drum is used effectively only for charging and exposure.

The invention will now be explained further by reference to an illustrative embodiment thereof shown schematically in the accompanying drawing, in which FIG. 1 is a schematic assembly view, in transverse cross-section, showing principal parts of the illustrative embodiment;

FIG. 2 is a schematic perspective view of certain web feeding and web cutting elements; and

FIG. 3 is a schematic diagram of a means for driving the web propelling elements.

Referring to FIG. 1, the llustrated copying apparatus makes use of a centrally supported rotatable hollow drum 1 having a storage roll 2 of light-sensitive or sensitizable web material mounted inside the drum, as on a rotatable roll core 2a axially aligned with the shaft of the drum. The web material is drawn from the roll 2 over a rounded edge 3a of a slot 3 formed in the peripheral wall of the drum, thence over the outer surface of the drum, and then between two rollers 4 and 5 which are carried by the drum in the region of the slot 3. Roller 4 is pivoted in a yoke 16 which can swivel in the end walls of drum 1. Roller 5 is rotatable in those walls about its own axis.

While the roller 4 is held away from roller 5, the end of the web material trained about the drum is drawn web material is thus clamped between the rollers 4 and 5.

Preferably, a second swivel yoke 18 supported by bearings and carrying a guide roller 19 is also fitting inside the drum 1. By means of springs 20 acting on the yoke 18, roller 19 continuously exerts a tension on the web material extending from roll 2 over the curved side wall 3a of slot 3, so that no slack will exist in the length of the web trained upon the drum. Thus, the web is always held taut and smooth on the drum surface even though there may be tendencies for slack to develop in the web material due, for example, to absorption of moisture from the surrounding atmosphere.

- The length of the web trained over the drum surface constitutes a photoconductive layer thereon. Disposed about the region traversed by this layer in each revolution of the drum are several processing stations, including station 6 for charging the web material, station 7 where conventional means may be provided for imagewise exposing it to light, station 8 for developing the resultant electrostatic image into a powder image, and station 9 wherein the powder image can be transferred to copying material 10. Finally, the web material is brushed clean at station 11 and thus prepared for making another image.

The drum 1 makes one revolution for each copying operation, while the web material remains stretched in fixed position on the drum surface so as to traverse the various stations mentioned. The copying with a given length of the web material can be repeated a large number of times, until deterioration of the quality of theused web material makes replacement of it desirable or necessary. At this stage, replacement of the used length of the web material can be readily effected as follows:

The drum is stopped in a position such as that shown in FIG. 1, in which the rollers 4 and are situated approximately opposite to a set of web feeding rollers 12 and 13 mounted at a fixed location outside the drum. The rollers 12 and 13 are arranged so that, when driven, they can grip an end of the web material between themselves and propel the material away from the drum 1. When the drum is thus stopped, the rollers 4 and 5 are started in rotation relative to the drum, e.g., by driving roller 5 so that it will drive-roller 4 by friction. The web material engaged by rollers 4 and 5 is thus drawn forward from and over the drum surface, while a corresponding length of fresh web material is unwound from the roll 2 and trained over the surface of the drum.

During this displacement, the used web material is passed outwardly between roller 5 and a guide 15 on the drum and is directed over a fixed curved guide 14, mounted outside the drum, which leads the web material in a curved path to a location where it is engaged between the rollers 12 and 13. These fixed rollers then grip the material and propel it away, for example in the direction of a scrap bag.

When the used length of the web material has been thus drawn away from the drum surface and replaced by a fresh length of the material, the rollers 4 and 5 are stopped while the rollers 12 and 13 are still being driven. The lead of the web extending between the two sets of rollers is thus drawn taut, as indicated by dashed lines in FIG. 1, and this tightening of it presses the web material against a knife-edge 15a formed along the outer edge of guide 15 secured to the drum. The length of web material propelled away from the drum is thus cut off, leaving a new free end of the web disposed between roller 5 and guide 15 in position to be fed against guide 14 and thence between rollers 12 and 13 when the drum is stopped again after a subsequent series of copying operations has been effected by use of the fresh length of web material. 1

In an attractive embodiment, as indicated in FIG. 2, the guide 15 is curved so that it partially embraces the roller 5, and its outer edge which forms the cutting edge 15a is serrated and tapered to a point at a location across the position towards which the web material is pulled when it is drawn taut by the rollers 12 and 13. The rollers 12 and 13 may be rotated continuously, or they may be started simultaneously with the rollers 4 and 5 and stopped soon after the driving of therollers 4 and 5 is discontinued. Variousmeans suitable for driving the rollers at the requiredtimes will be apparent to the skilled engineer. For instance, as indicated schematically in FIG. 3 of the drawing, a driven pinion 22 kept in driving engagement with a wheel 23 fixed to the shaft 13a of roller 13 may be displaced angularly to and from a position in which, when the drum is in its stopped position shown in FIG. 1, pinion 22 will also be in driving engagement-with a wheel 24 fixed to the shaft 5a of roller 5.

The invention can be carried out by the use of a web cutting means, or knife, of any of various forms or kinds differing from that provided by edge 15a of guide 15, or even without using a cutting means for severing the used length of the web material. The rollers 12 and 13 could simply tear off the used web material, but this manner of operation is less satisfactory in regard to assuring a desirable location of the new free end formed on the web material by the separation. The severance of the used material by tearing it off can be effected either by continuing the rotation of rollers 12 and 13 while the drum stands still or by re-starting the rotation of the drum while the used web material is being held by those rollers. Furthermore, the used material can be cut off in the latter manner of operation, for instance by means of a knife-edge 21 fixed across the path traversed by the web lead between roller 5 and rollers 12 and 13 when rotation of the drum 1 is resumed.

What is claimed is:

1. Copying apparatus comprising a rotatable hollow drum having a slot in its peripheral wall, a roll of lightsensitive or sensitizable continuous web material mounted rotatably inside said drum, a length of said material. being trained from said roll through said slot and thence upon and about the outer surface of said drum, means mounted on said drum in the vicinity of said slot for engaging and holding an end portion of said length so trained about said drum, and processing means disposed about said drum and operable during each revolution there of to form an image on the web material upon said surface and to transfer such image to a copy material, wherein said holding means includes means drivable when said drum is in a certain rest position thereof to displace the web material engaged by said holding means outwards from said drum and said apparatus further comprises means spaced away from said drum at a fixed location outside said drum for propelling away from said drum the web material displaced outwards therefrom by said web displacing means when said drum is in said rest position thereof, whereby a used length of the web material is removed from said outer surface and simultaneously a corresponding length of web material is drawn from said roll and trained upon said surface in replacement of said used length thereon, means operable when said drum is in said rest position for driving said web displacing means and said propelling means simultaneously, and means for severing the said used length at a location adjacent to said drum between said web displacing means and said propelling means.

2. Copying apparatus according to claim 1, and means operable to discontinue the driving of said web displacing means while continuing the driving of said propelling means, so that the web material being propelled by the latter will be severed from the web material held by said holding means.

3. Copying apparatus according to claim 1, said severing means comprising means for cutting through web material leading from said web displacing means to said propelling means.

4. Copying apparatus according to claim 1, said holding means comprising a roller and a clamping member normally bearing against said roller so as to grip said web material therebetween, said roller constituting at least part of said web displacing means and being rotatable to displace the web material engaged thereby outwards from said drum via said slot.

5.Copying apparatusaccording to claim 4, further comprising guide means for directing in a curved path the web material moved from said roller to said propelling means, said serving means including a knife positioned to cut through that web material at a location near to said roller when the same is drawn taut between said roller and said propelling means.

6. Copying apparatus according to claim 5, said knife having a serrated cutting edge.

7. Copying apparatus according to claim 5, further comprising a curved guide member mounted on said drum and partially embracing said roller, said guide member having a serrated outer edge constituting said knife, said edge extending to a point over a part of said curved path of the web material.

8. Copying apparatus according to claim 4, said clamping member being displaceable away from said roller in order to interrupt the gripping action and to facilitate threading of a free end portion of the web material therebetween.

9. Copying apparatus according to claim 1, further comprising means in said drum for tensioning the web material trained onto said drum from said roll. 

1. Copying apparatus comprising a rotatable hollow drum having a slot in its peripheral wall, a roll of light-sensitive or sensitizable continuous web material mounted rotatably inside said drum, a length of said material being trained from said roll through said slot and thence upon and about the outer surface of said drum, means mounted on said drum in the vicinity of said slot for engaging and holding an end portion of said length so trained about said drum, and processing means disposed about said drum and operable during each revolution there of to form an image on the web material upon said surface and to transfer such image to a copy material, wherein said holding means includes means drivable when said drum is in a certain rest position thereof to displace the web material engaged by said holding means outwards from said drum and said apparatus further comprises means spaced away from said drum at a fixed location outside said drum for propelling away from said drum the web material displaced outwards therefrom by said web displacing means when said drum is in said rest position thereof, whereby a used length of the web material is removed from said outer surface and simultaneously a corresponding length of web material is drawn from said roll and trained upon said surface in replacement of said used length thereon, means operable when said drum is in said rest position for driving said web displacing means and said propelling means simultaneously, and means for severing the said used length at a location adjacent to said drum between said web displacing means and said propelling means.
 2. Copying apparatus according to claim 1, and means operable to discontinue the driving of said web displacing means while continuing the driving of said propelling means, so that the web material being propelled by the latter will be severed from the web material held by said holding means.
 3. Copying apparatus according to claim 1, said severinG means comprising means for cutting through web material leading from said web displacing means to said propelling means.
 4. Copying apparatus according to claim 1, said holding means comprising a roller and a clamping member normally bearing against said roller so as to grip said web material therebetween, said roller constituting at least part of said web displacing means and being rotatable to displace the web material engaged thereby outwards from said drum via said slot.
 5. Copying apparatus according to claim 4, further comprising guide means for directing in a curved path the web material moved from said roller to said propelling means, said serving means including a knife positioned to cut through that web material at a location near to said roller when the same is drawn taut between said roller and said propelling means.
 6. Copying apparatus according to claim 5, said knife having a serrated cutting edge.
 7. Copying apparatus according to claim 5, further comprising a curved guide member mounted on said drum and partially embracing said roller, said guide member having a serrated outer edge constituting said knife, said edge extending to a point over a part of said curved path of the web material.
 8. Copying apparatus according to claim 4, said clamping member being displaceable away from said roller in order to interrupt the gripping action and to facilitate threading of a free end portion of the web material therebetween.
 9. Copying apparatus according to claim 1, further comprising means in said drum for tensioning the web material trained onto said drum from said roll. 